I have now downloaded the report and can see how we get these different amounts. It seems that losses in thermal generation and distribution contribute a significant part of this 220 m toe. If we had more renewables and less thermal generation (at least that without CHP???) then I expect we would not need 220 m toe to supply 153 m toe final energy consumption.

Anyhow, whatever amount we are starting with, I know we can dramatically reduce energy consumption and the 40% suggested by RC seems possible to me.

I'm also not expecting that we can convert to 80-100% renewables tomorrow, and expect we'll carry on with NG and nuclear for a long time as well.

Yes, 'demand' was a trivial error (corrected) but since supply=demand it's of no consequence.

Like it or not, the headline energy consumption of the UK is 220 million tons oil equivalent per annum (2010: Dukes page 13). And that's 120 kWh pppd.

Your figure of 153 million tons excludes all the energy we use in the production, transmission and distribution of electricity (Dukes para 1.14) But this is wrong, because at the very least you'd have to add the final delivered electricity energy on top of that number. And this aso ignores the basic point that we can't convert one energy source into any other form of energy at 100 % efficiency. I can't see that this distinction does anything but deliver a false impression of our energy needs, especially when the largest renewable energy production method we have at present (in terms of energy production) is a thermal process: biomass.

Edit: I suppose we can crudely guestimate the electrcity energy we need to add back in to the 153 million tons as 35 % of (220-153) million, assuming an overall generation/supply efficiency of 35 %. That would give us, crudely, 176 million tons, 96 kWhpppd.

So, reading again from DUKES p 13-14, of the 120 KWh pppd required to power the UK

42 KWh pppd is used (or wasted) just to supply that energy
27 KWh pppd is used directly by industry, service sectors and agriculture
29 KWh pppd is used directly in transport (I'm not quite clear if that includes car fuel)
22 KWh pppd is used directly in our homes (average: some of us are ahead!)

I am not quite sure of your point AIC about the double counting of energy used in energy production, for example the "primary" chart mentions "net inputs for conversion".

I suppose we would ideally use CHP for all our thermal generation but its not so easy is it.

pepperman makes the point that final energy consumption is 153 million tons oil - supported by Dukes

I make the point that net energy consumption or total energy burn is 220 million tons oil (again, supported by Dukes)

There's no dispute here. The difference, 67 million tons oil is the energy burnt to produce electricity. But my final point is that that 67 million tons burnt at 35 % efficiency should give us back 23.5 million tons of oil energy in the form of electricity and I don't see that being added back into the final energy figure.

The more I think about this difference (between the 220 and 153 figures), the more I think it's a false or weak argument. It's true that renewables in the form of tide, wave, wind, solar generation is seemingly 100 % efficient at the point of generation - no fossil fuel in, nice electricity out. At that stage, pepperman's point seems to hold great validity.

But then the difficulties arise.

Apart from tide and biomass, no renewable system delivers electricity energy as we want it - i.e. on demand, at any time, often with great variations in magnitude. To overcome that, we'll have to have storage - and the best we can do is pumped storage 75 % efficient. And we'll have to wheel the electrical power all the way to the storage facility, and back again! Now it's still not fossil fuel, but this will incur large capital costs and somewhere in all this we're going to have to count the cost of what we're doing.

Further, we need to address transport and it's usual to say: electric vehicles. But now we have to convert the renewable electrical energy into a form of chemical or physical storage and then convert it back again. So: the old problem of energy conversion efficiency arises all over again.

The effect of both of these will be to elevate the target for renewable energy production above the 153 million tons of oil figure. You have to do this to cover the losses in storage and energy conversion. My hunch is that you'll be back at the 220 million tons figure.

I see now how the losses in energy generation are a big part of the discrepancy between the "total actual energy input into the UK" and my expectation of what that might be working up from "my energy use plus what seems reasonable for indirect energy use".

Are you saying that DUKES is wrong concerning energy losses in electricity production? Their pie chart for total energy includes "net conversion energy" - surely that does not include the electricity actually produced and supplied to the user?

I do agree its likely that we'll need to add some extra energy requirement to deal with the intermittency issue at high renewables penetration. Hopefully not as much as with thermal generation!

We can reduce primary energy demand in so many ways so hopefully we won't actually be aiming for 220 m toe in total. Indeed the long term future has to be imagined without fossil fuels entirely (and maybe also without nuclear) so we have to find a way to manage with renewables.

kenneal: I think there will be a revolt if they try to ram LEDs down our throats.

Insulation: it's great saying we can just go ahead and insulate our houses, but my experience is that with older houses they all seem to have unique problems. For example - how would you tackle this:
Leeds: Edwardian, end-of-terrace, three storey house, solid brick walls 50 cm thick throughout. End wall is unbroken, high quality original brickwork, facing directly onto narrow, public pavement. Inside the house, door and window casements butt directly to the end brick face. Just how do you insulate the wall cost effectively?

Why add "cost effectively"? Gas costs are about to rise by 19% from one supplier and all the others will follow. We can surmise from the growth rate of China that they are going to be importing a massive extra amount of fuel, be it coal, oil or gas, in the future which will jack up prices even further. The UK has a rapidly increasing balance of payments problem and a reducing indigenous gas supply. A one off payment to reduce the nations fuel consumption by 40% must be worth a lot of money.

A national insulation scheme would reduce the costs of an installation by as much as 50% over a single job on an individual house. For a start you could lose the VAT: then come economies of scale of buying the materials: then come the efficiencies of labour on a larger scale work site; savings by doing a pair of semis or a whole terrace rather than individual houses and separately edging each house.

Your Leeds house? Insulate it externally covering all the lovely brickwork so that the occupants can live there in comfort. What would you rather do? Live in comfort or die of hypothermia, because you can't afford your fuel bills, while looking at a nice brick wall? Narrow pavement? Widen it and narrow the road. If people can't afford to heat their houses they won't be driving so many cars around either so the parking space will become a child's play area.

The nation can't afford our present fuel bill let alone individual families. so why doesn't the nation do something about it? We can afford the insulation bill if the government prints the money, distributes it through the Green Bank and taxes it back from family's savings. That wouldn't be inflationary. It would also give a temporary boost to the economy for a few years and keep the banks going for a little while longer. It would leave a lasting legacy of longer lived, fuel efficient housing into our pauper's future._________________BLOG

It is very, very, very serious indeed. This is the big one!" Professor Tim Lang, APPGOPO, 25/03/08. And he was talking about food, not oil or the economy!

Re your proposal. So, you assume you can take width off the pavement - hope the planning people will accept that? They won't. They've tried that tack, and the response is no surprise. And spoil/hide the brickwork? I think a lot of people will find that unacceptable. And you've provided no costing.

Not impressed at all.

I'll do my side of the calculations.
The U value is 1.55, width of wall 7 metres, height 6.5 m, take average temperature difference to be 10, annual energy loss is then 6.2 MWh. With heating at 7p/kWh (let's stick with today's costs and avoid hairy-fairy speculation about rpi versus fuel inflation) over 20 years your budget for alleviation will be £8500. That's with no DCF (which is mad, but we've got to give you a chance).

It's the idea that you focus only on a prime energy figure of 153 million toe as the target to reach; it's wrong because that figure has chopped out the electrical energy used by industry and homes.

Seeing if we can generate enough from renewables will be interesting - McKay's a good start.

Sorry, don't get this. It seems to me that the electricity coming out of the generating industry and supplied to users in homes and industry would be included in the 153 m toe. At least this is suggested to me by chart 1.3 (18% of final energy consumption is electricity).

Since I'm keen we move to a sustainable energy supply, for me the question is not how to make 220 m toe equivalent from renewables, but to see how much renewables can give us and work with that, plus whatever else we can muster from the least environmentally damaging non-renewable sources. McKay is a useful report and the CCC latest review is also predicts a maximum feasible generation from UK renewables which I think is similar to the 30 KWh pppd of McKay. We may consider some import of renewables but why should we get a lot from other countries that need it too.

A massive reduction in energy use is not an easy road. For heating homes, we could have some richer people affording a passivhaus type approach that kenneal promotes, but a lot of other people may just try to manage with less heating and that's a big concern.

Perhaps there are lower cost solutions that don't require a whole house retrofit. Do we really need to heat a whole home to 18C plus in order to maintain the comfort and health of the occupants? I am thinking heating just the living room, dressing up warm at all times, finding ways of avoiding condensation creating problems for the fabric of the house, bring back four poster beds with proper curtains....there have been threads about this type of thing on PS.

Yes, agreed, I was getting confused by some of the statements in sections 1.12 -1.14, and I didn't spot the annotation to the RHS diagram of 1.3. So there's no need to top up the 153 mtoe with any figure for electricity use.

But I still think, for the same reasons I've given above, that 153 mtoe is a misleading first target for renewables (notwithstanding any efficiency/cuts you may make) because the real energy burn behind that 153 mtoe is 220 mtoe, the difference being the energy conversion loss for electricity. Once you try to use electricity to drive cars, you face conversion problems and losses, and since renewable energy is almost always never on-demand (the exceptions being tidal and biomass) you again face storage losses. In other words, if you did nothing about cutting demand, providing a renewable supply of 153 mtoe would not meet our needs anymore than burning 153 mtoe fossil fuels will meet our present needs.

McKay p 204 diagram 27.1 appears to show 2050 transport needs as 20 kWhpppd of which 2 kW will be biofuels, and 18 kWhpppd will be electricity - implying, to me, 100 % storage efficiency - he does say that transport will be four times more efficicient than now. That's a very optimistic projection!

OK, I was not just seeing things in the DUKES report! Sure, we need to take account of any losses in storage if storage becomes a big part of the system.

McKay sets as a target for all his scenarios to generate 50 KWh pppd in electricity. All of them are challenging and ambitious.

For transport, it it not the case that electric engines are several times more efficient than ICE?

I was hoping that BBC article would manage the whole thing without a quote from those cheeky REF chappies but yet again...certainly we should develop the grid further so its never necessary to discard output from windfarms.

Re your proposal. So, you assume you can take width off the pavement - hope the planning people will accept that? They won't. They've tried that tack, and the response is no surprise. And spoil/hide the brickwork? I think a lot of people will find that unacceptable. And you've provided no costing.

Not impressed at all.

You're assuming here that the people in the house are carrying out this work as individuals, not as part of a national mobilisation programme as envisaged by other people in this thread. If all the houses in that street in Leeds were insulated together, they'd all end up with the same exterior colour, so the street would at least keep its unity, even if it looked different (erm and RenewableMum grew up in those Leeds streets so don't just assume I don't give a stuff about them).

Roads may very well get narrower: where I live, they're contemplating a city-wide 20mph speed limit on small streets, and pedestrianisation of the city centre. It's all part of a general trend, and it seems to be being pushed on a quality-of-life ticket, rather than a Climate-Change or PO one._________________Soyez réaliste. Demandez l’impossible.
Space and SpaceabilityThe Year-Long Lunch Break

The more I think about this difference (between the 220 and 153 figures), the more I think it's a false or weak argument.

It's not false or weak. These are important distinctions to make but renewables bashers conveniently talk about primary supply which makes the task appear much more challenging than it is.

Switching to renewable electricity gives you an instant efficiency boost because you're not frittering away vast quantities of heat. Same goes for electrification of transport which would approximately halve transport consumption simply by getting rid of the combustion engine.

That's far too simplistic, as I've pointed out several times in this very thread. There are two problems with your claim that we can entirely remove the energy losses associated with energy conversion processes simply by 'going renewable'.

I'll spell it out agin.

Apart from tide and biomass none of the renewable energy sources provide energy as it is required. Indeed, they suffer from intermittancy and cannot provide the grid stabilising systems we require. To make provision for this you will need energy storage on a vast scale. You can do this using electric vehicle batteries (albeit, I'd have thought the range of these vehicles was already quite limited) or by using pumped storage. Both of these are energy conversion processes and they involve an energy loss.

And if you want to get rid of the inefficient combustion engine in transport (the theoretical efficiency of diesel engines is 75 % and practical engines of 50 % are available) then I'll assume we're taking storage of electricl energy in batteries again - see above. Hydrogen storage is a non starter given the efficiencof hydrogen production.

My estimates for these processes would be:

typical pumped storage efficiency is 75 %, with with transmission out and back - 2 % each way, dependent upon the distance between the pumped storage and load,
and
battery storage will 50-80 % efficient dependent on battery age, prior charge, charge rate, etc with an additional 7 % loss in transmission and distribution (assuming the vehicle batteries are embedded in local grids).

So our starting point for the energy we have to provide, or reduce, is not the current 153 mtoe demand (the sum of our thermal and electrical energy demands), but a larger value, somewhat toward the 220 mtoe supply (the sum of our thermal energy demand and provision for the production of our electrical energy demand) that we currently consume.

So we should start with a realistic target of approximately 220 mtoe energy - to be either procured, or the target trimmed.